AUTHOR=Si Bing , Dumkrieger Gina , Wu Teresa , Zafonte Ross , Dodick David W. , Schwedt Todd J. , Li Jing 

TITLE=A Cross-Study Analysis for Reproducible Sub-classification of Traumatic Brain Injury

JOURNAL=Frontiers in Neurology

VOLUME=Volume 9 - 2018

YEAR=2018

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2018.00606

DOI=10.3389/fneur.2018.00606

ISSN=1664-2295

ABSTRACT=Objective: To identify reproducible sub-classes of traumatic brain injury that correlate with patient outcomes. 
Methods: Two TBI datasets from the Federal Interagency Traumatic Brain Injury Research (FITBIR) Informatics System were utilized, Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) Pilot and Citicoline Brain Injury Treatment Trial (COBRIT). Patients included in these analyses had closed head injuries with Glasgow Comas Scale (GCS) scores of 13-15 at arrival to the Emergency Department (ED). Sparse hiearchical clustering was applied to identify TBI sub-classes within each dataset. The reproducibility of the sub-classes was evaluated by investigating similarities in clinical variable profiles and patient outcomes in each sub-class between the two datasets, as well as by using a statistical metric called in-group proportion (IGP). 
Results: Seven TBI sub-classes were identified in the first dataset. There were between-class differences in patient outcomes at 90 days (Glasgow Outcome Scale Extended (GOSE): p<0.001) and 180 days (Trail Making Test (TMT): p=0.03). Four of 7 sub-classes were reproducible in the second dataset with very high IGPs (94%, 100%, 99%, 97%). Seven TBI sub-classes were also identified in the second dataset. There were significant between-class differences in patient outcomes at 180 days (GOSE: p=0.024; Brief Symptom Inventory (BSI) p=0.007; TMT: p<0.001). Three of 7 sub-classes were reproducible in the second dataset with very high IGPs (100% for all). 

Conclusions: Reproducible TBI sub-classes were identified across two independent datasets, suggesting that these sub-classes exist in a general population. Differences in patient outcomes according to sub-class assignment suggest that this sub-classification could be used to guide post-TBI prognosis.